Refine web.canonicalUrl documentation

src/main/distrib/data/gitblit.properties

@@ -844,8 +844,18 @@ realm.minPasswordLength = 5
 # SINCE 0.5.0
 web.siteName =
 
-# The canonical url of your Gitblit server to bs used in email notifications.
-# e.g. web.canonicalUrl = https://demo-gitblit.rhcloud.com
+# The canonical url of your Gitblit server to be used in repository url generation,
+# RSS feeds, and all embedded links in email and plugin-based notifications.
+#
+# If you are running Gitblit on a non-standard http port (i.e. not 80 and not 443)
+# then you must specify that port in this url otherwise your generated urls will be
+# incorrect.
+#
+# The hostname of this url will be extracted for SSH and GIT protocol repository
+# url generation.
+#
+# e.g. web.canonicalUrl = https://dev.gitblit.com
+#      web.canonicalUrl = https://dev.gitblit.com:8443
 #
 # SINCE 1.4.0
 web.canonicalUrl =